The present invention relates to apparatus for regulating the flow of liquids through the outlet openings of sinks, tanks or other types of vessels. More particularly, the invention relates to improvements in valve assemblies which can be utilized to regulate the outflow of liquids through outlet openings provided in the bottom walls or liquid-containing or storing vessels.
Heretofore known valve assemblies which are used for the above outlined purpose comprise a valve element which is movable up and down between open and closed positions with respect to an annular seat surrounding the outlet opening in the bottom wall of the liquid-containing vessel. The upward movement of the valve element can be effected by means of a rod which is to be raised (pulled) in order to lift the valve element off the seat. It is also known to employ an actuating device which must be depressed in order to lift the valve element off the seat; this necessitates the provision of a linkage which moves the valve element upwardly in response to downward movement of the actuating device.
A drawback of the aforedescribed valve assemblies is that, in order to initiate the outflow of liquid, it is necessary to apply a rather pronounced force which is required to lift the valve element against the static pressure of the liquid column thereabove, especially if the level of liquid in the vessel is high.